480 



Transactions. 



Commercial Valuation. 



The commercial valuation of meat-extracts, however, is not based upon 

 the results of an extensive and detailed identification of the various 

 nitrogenous constituents which give the value to an extract, but upon a 

 consideration of the colour, flavour, and the proportion of the extract 

 soluble in 80 per cent, alcohol ; it is the amount of the latter which to a 

 large extent determines the value to the manufacturer of the meat-extract. 



The method has been criticized adversely from time to time as being 

 unsound in principle from a scientific point of view ; in commercial 

 practice,, however, this determination showed results which were in general 

 accord with the demand of the purchaser, although the underlying reason 

 was not apparent. 



Nitrogenous Constituents. 



It is only recently, however, that methods of analyses have been 

 developed which enable the study of nitrogenous constituents to be carried 

 out with a reasonable degree of accuracy and detail. 



In the results to be described the following methods were used. For 

 the determination of the moisture, mineral salts, chlorine, nitrogen, meat- 

 bases, the methods outlined by one of us (A. M. W.) (3) were used. The 

 " meat-base " nitrogen is that of the tannin-salt filtrate after deducting 

 the ammoniacal nitrogen determined by the magnesium-oxide distillation 

 method. This probably gives results lower than the actual for the "meat- 

 base " nitrogen, for the reason that the magnesium-oxide distillation method 

 for the determination of the ammoniacal nitrogen probably gives results 

 which are too high. The results of a comparative study of the magnesium- 

 oxide distillation method, and the Folin aeration method applied to the 

 determination of ammoniacal nitrogen in meat-extracts, will be discussed 

 later. As, however, in most of the recent work upon flesh products the 

 magnesium-oxide method has been used, the results will be comparable 

 with those of other workers. For the determination of the 80 per cent, 

 alcoholic precipitate and the soluble extract the method described by 

 Thorpe (4) was used. 



Calculated to Moisture-free Basis. 



soluble in 80 per cent, alcohol, 61-4 per cent, of the total solids, 57-7 per 

 cent, of the total mineral salts, and 63-1 per cent, of the total nitrogen, 



